velcro - b/c they are easier to adjust to how you want them - faster and better
in terms of brands: English Bulldog and Reisport grips are good, 10-0 grips not so much b/c they don't have those flaps in the holes like the other grips brands do, and the flaps do help in keeping the grips in place! the flaps are especially good when the holes are too big for you to begin with and you have to 'sew tape' them (like someone said in that thread on what to do if your grips are too big for you)
Baile grips have those foam pads in them - which aren't so good b/c wrist guards work better, and having that double padding affects the grips positioning